The rotary piston engine is an internal combustion engine which operates on the same general principal as a reciprocating piston internal combustion engine. In a conventional internal combustion engine, a reciprocating piston is coupled to a connecting rod for producing rotation and torque. In a rotary piston engine, torque is produced by means of a rotating piston which avoids the necessity for alternately accelerating and retarding a large mass as occurs when an ordinary piston moves to and fro. Consequently, the forces of inertia associated with the reversing stroke movement of a conventional reciprocal piston engine are avoided. As a result, higher speeds of rotation are possible in a rotary piston engine, and stresses which are imposed by the reversing stroke movement are avoided.
Another limitation of conventional internal combustion engines in general is their inability to provide high torque at low speed and relatively constant torque over a wide range of speed.